Fire assisted powered egia handle

ABSTRACT

A handle assembly includes a trigger assembly, a motor, and a drive assembly. The trigger assembly includes a trigger, a head portion, and a deflection member interconnecting the trigger and the head portion such that a load applied to the trigger causes the deflection member to flex to define a gap between the trigger and the head portion. The motor is configured to be activated based on a size of gap defined by the trigger and the head portion. The drive assembly includes a clamping gear, a firing gear assembly, a drive gear, and a rack. When a button of the trigger assembly engages the clamping gear, actuation of the trigger advances the rack by a first distance, and when the button engages the firing gear assembly, actuation of the trigger advances the rack by a second distance greater than the first distance.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 62/990,506 filed Mar. 17, 2020, the entire disclosure of which is incorporated by reference herein.

TECHNICAL FIELD

The disclosure relates to a surgical instrument, and more particularly, to an endoscopic surgical stapling instrument having a power assisted handle assembly.

BACKGROUND OF RELATED ART

Minimally invasive surgery has become increasingly popular in recent years. Minimally invasive surgery eliminates the need to cut a large incision in a patient, thereby reducing discomfort, recovery time, and many of the deleterious side effects associated with traditional open surgery. Minimally invasive viewing instruments (e.g., laparoscopes and endoscopes) are optical instruments to facilitate the viewing of internal tissues and/or organs.

Laparoscopic surgery involves the placement of a laparoscope in a small incision in the abdominal wall of a patient to view the surgical site. Endoscopic surgery involves the placement of an endoscope in a naturally occurring orifice (e.g., mouth, nose, anus, urethra, or vagina) to view the surgical site. Other minimally invasive surgical procedures include video assisted thoracic surgery and cardiovascular surgery conducted through small incisions between the ribs. These procedures also utilize scopes to view the surgical site.

Various types of surgical instruments used to surgically join tissue are known in the art, and are commonly used, for example, for closure of tissue or organs in transection, resection, anastomoses, for occlusion of organs in thoracic and abdominal procedures, and for electrosurgically fusing or sealing tissue.

One example of such a surgical instrument is a surgical stapling instrument, which may include an anvil assembly, a cartridge assembly for supporting an array of surgical staples, an approximation mechanism for approximating the cartridge and anvil assemblies, and a firing mechanism for ejecting the surgical staples from the cartridge assembly.

SUMMARY

In accordance with the disclosure, a handle assembly for use with a surgical stapling instrument includes a trigger assembly, a motor, and a drive assembly. The trigger assembly includes a trigger transitionable between a distal position and a proximal position, a head portion, a button slidably supported in the head portion, and a deflection member interconnecting the trigger and the head portion such that a load applied to the trigger causes the deflection member to flex to define a gap between the trigger and the head portion. The motor is configured to be activated based on a size of gap defined by the trigger and the head portion. The drive assembly includes a clamping gear, a firing gear assembly, a drive gear, and a rack. The clamping gear is operatively coupled to the trigger such that actuation of the trigger causes rotation of the clamping gear when the button of the head portion engages the clamping gear. The firing gear assembly is operatively coupled to the trigger such that actuation of the trigger causes rotation of the firing gear assembly when the button of the head portion selectively engages the firing gear assembly. The drive gear is operatively coupled to the clamping gear, the firing gear assembly, and the motor. The rack is engaged with the drive gear such that rotation of the drive gear causes axial displacement of the rack. When the button of the trigger assembly engages the clamping gear, actuation of the trigger advances the rack by a first distance, and when the button engages the firing gear assembly, actuation of the trigger advances the rack by a second distance greater than the first distance.

In an aspect, the firing gear assembly may include a firing gear and an alignment member defining proximal and distal button slots configured to selectively receive the button of the trigger assembly.

In another aspect, when the button engages the clamping gear, actuation of the trigger may cause rotation of the clamping gear and the firing gear assembly such that the button is aligned with the proximal button slot of the alignment member.

In yet another aspect, the firing gear may define an arc having teeth at a peripheral portion thereof.

In still yet another aspect, the firing gear and the alignment member may be rotatable as a single construct.

In still yet another aspect, the clamping gear may define a cutout positioned to engage the button of the trigger assembly.

In an aspect, the head portion may be pivotably supported by a first pivot pin.

In another aspect, the clamping gear and the firing gear may be rotatably supported on the first pivot pin.

In yet another aspect, the head portion may further include a first spring to bias the button laterally outwards.

In still yet another aspect, the trigger may define a cavity that receives at least a portion of the deflection member.

In still yet another aspect, the head portion may be coupled to a second spring to bias the trigger towards the distal position.

In an aspect, the head portion may include a sensor to measure the size of a gap defined between the trigger and the head portion.

In another aspect, the motor may be configured to be activated when the button is engaged with the firing gear assembly.

In yet another aspect, the handle assembly may further include a processor in communication with the sensor to activate the motor based on the size of gap defined between the trigger and the head portion.

In accordance with another aspect of the disclosure, a handle assembly for use with a surgical stapling instrument includes a trigger assembly, a motor, and a drive assembly. The trigger assembly includes a trigger and a head portion including a button movable between first and second positions. The head portion and the trigger define a gap commensurate with a load applied to the trigger. The motor is configured to be activated based on a size of gap defined by the trigger and the head portion. The drive assembly includes a clamping gear, a firing gear assembly, a drive gear, and a rack. The clamping gear is operatively coupled to the trigger such that actuation of the trigger causes rotation of the clamping gear. The firing gear assembly is configured to engage the button such that actuation of the trigger causes rotation of the firing gear assembly. The drive gear is operatively coupled to the clamping gear, the firing gear assembly, and the motor. The rack is configured to engage the drive gear such that rotation of the drive gear causes axial displacement of the rack. When the button engages the clamping gear, actuation of the trigger advances the rack by a first distance, and when the button engages the firing gear assembly, actuation of the trigger advances the rack by a second distance greater than the first distance and activates the motor that assists advancement of the rack.

In an aspect, the firing gear assembly may include a firing gear and an alignment member defining proximal and distal button slots configured to selectively receive the button of the trigger assembly.

In another aspect, the button may engage the distal button slot of the alignment member when the trigger is actuated to advance the rack by the second distance.

In accordance with yet another aspect of the disclosure, a surgical stapling instrument includes a loading unit, a handle assembly, and a drive rod. The loading unit includes first and second jaws having a staple cartridge assembly and an anvil assembly, respectively. The handle assembly includes a housing, a trigger assembly, a motor, and a drive assembly. The trigger assembly includes a trigger and a head portion pivotably coupled to the housing and movable relative to the trigger. The head portion includes a button slidably supported in the head portion. The motor is configured to be activated based on a gap defined between the trigger and the head portion. The drive assembly includes a clamping gear, a firing gear assembly, a drive gear, and a rack. The clamping gear is operatively coupled to the trigger such that actuation of the trigger causes rotation of the clamping gear when the button of the head portion engages the clamping gear. The firing gear assembly is operatively coupled to the trigger such that actuation of the firing gear assembly causes rotation of the firing gear assembly when the button of the head portion engages the firing gear assembly. The drive gear is operatively coupled to the clamping gear, the firing gear assembly, and the motor. The rack is configured to engage the drive gear such that rotation of the drive gear causes axial displacement of the rack. The drive rod operatively couples the rack with the loading unit. When the button engages the clamping gear, actuation of the trigger advances the drive rod by a first distance to clamp the first and second jaws together, and when the button engages the firing gear assembly, actuation of the trigger advances the drive rod by a second distance greater than the first distance to fire staples from the staple cartridge assembly.

In an aspect, the firing gear assembly may include a firing gear and an alignment member defining proximal and distal button slots configured to selectively receive the button of the trigger assembly.

In another aspect, when the button engages the clamping gear, actuation of the trigger may rotate the clamping gear and the firing gear assembly such that the button is aligned with the proximal button slot of the alignment member.

In yet another aspect, the button may engage the distal button slot of the alignment member when the trigger is actuated to advance the rack by the second distance.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the disclosure are illustrated herein with reference to the accompanying drawings, wherein:

FIG. 1 is a perspective view a surgical stapling instrument in accordance with the disclosure;

FIG. 2 is a partial perspective view of a handle assembly of the surgical stapling instrument of FIG. 1 with a first housing half of the handle assembly removed;

FIG. 3 is a partial perspective view of the handle assembly of the surgical stapling instrument of FIG. 1 with a second housing half of the handle assembly removed;

FIG. 4 is an exploded perspective view of the handle assembly of the surgical stapling instrument of FIG. 1 with parts separated;

FIGS. 5 and 6 are perspective views of a firing gear assembly of the handle assembly of FIG. 4;

FIG. 7 is a perspective view of a clamping gear of the handle assembly of FIG. 4;

FIGS. 8 and 9 are perspective views of a button of the handle assembly of FIG. 4;

FIG. 10 is a partial perspective view of the handle assembly of FIG. 3 cut along section line 10-10 of FIG. 3;

FIG. 11 is a side view of the handle assembly of FIG. 4 with the housing removed;

FIG. 12 is an enlarged cross-sectional view of the indicated area of detail of FIG. 11;

FIG. 13 is a perspective view of the handle assembly of FIG. 11 cut along section line 13-13 of FIG. 11;

FIG. 14 is a side view of the handle assembly of FIG. 4 with the second housing half removed;

FIG. 15 is a cross-sectional view of the handle assembly of FIG. 12, illustrating deflection of a deflection member of the trigger assembly;

FIG. 16 is a side view of the handle assembly of FIG. 14 with the housing removed;

FIG. 17 is an enlarged side view of the indicated area of detail of FIG. 16;

FIG. 18 is a side view of the handle assembly of FIG. 4 with the housing removed, illustrating a drive assembly of the handle assembly when a loading unit is in a clamped configuration;

FIG. 19 is a partial perspective view of the handle assembly of FIG. 16, illustrating a tab of the button received through a proximal button slot of an alignment member of the firing gear assembly;

FIG. 20 is a perspective view of the handle assembly of FIG. 16 cut along section line 20-20 of FIG. 19;

FIG. 21 is a perspective view of the handle assembly of FIG. 16 with the housing removed, illustrating resetting of the trigger assembly when the loading unit is in the clamped configuration;

FIG. 22 is a side cross-sectional view of the handle assembly of FIG. 16, illustrating the tab of the button operatively engaging the firing gear assembly;

FIG. 23 is a partial side view of the handle assembly of FIG. 16, illustrating the tab of the button engaging a distal slot of the alignment member of the firing gear assembly;

FIG. 24 is a cross-sectional view of the handle assembly of FIG. 16, illustrating the button aligned with a cutout of the clamping gear after the firing of staples from the loading unit; and

FIG. 25 is a handle assembly in accordance with another aspect of the disclosure.

DETAILED DESCRIPTION

The disclosed surgical access device is described in detail with reference to the drawings, wherein like reference numerals designate corresponding elements in each of the several views. As used herein, the term “distal” refers to that portion of the instrument, or component thereof which is farther from the user while the term “proximal” refers to that portion of the instrument or component thereof which is closer to the user.

With initial reference to FIG. 1, a handle assembly for use with a surgical device, in the form of a surgical stapling instrument 10 is shown generally as 100. The handle assembly 100 is adapted to be manually actuated by squeezing a trigger 112 up to a certain threshold of firing force. Upon reaching the threshold firing force, the handle assembly 100 is adapted to automatically provide powered actuation to assist a clinician in manually actuating the surgical stapling instrument 10. The depicted surgical stapling instrument fires staples, but it may be adapted to fire any other suitable fastener such as clips and two-part fasteners. Additionally, while the figures depict a linear fastener-applying surgical stapling instrument, other types of endoscopic surgical instruments including surgical stapling instruments are encompassed by the disclosure and are usable with the disclosed handle assembly 100. Details of a circular fastener-applying surgical stapling instrument are described in commonly-owned U.S. Pat. No. 8,011,554, the entire contents of which are hereby incorporated by reference herein.

With continued reference to FIG. 1, the surgical stapling instrument 10 generally includes the handle assembly 100, an elongate or endoscopic portion 30 extending distally from the handle assembly 100, and a loading unit 50 attachable to the endoscopic portion 30. The components of the surgical stapling instrument 10 may be formed from suitable biocompatible materials such as medical grade metals (e.g., stainless steel), polymeric materials (e.g., polycarbonate), or combinations thereof. The loading unit 50 includes a proximal portion 52 and an end effector 54 including jaws having a cartridge assembly 56 and an anvil assembly 58, respectively, disposed adjacent the proximal portion 52. The loading unit 50 may be configured as a single-use device that is discarded after use or sent to a manufacturer for reprocessing, a reusable device capable of being cleaned and/or sterilized for repeated use by the end-user, or a partially-single-use, partially-reusable device. With respect to partially-single-use or partially reusable devices, the anvil assembly 58 may be configured as a cleanable/sterilizable, reusable component, while the cartridge assembly 56 may be configured as a single-use, disposable/reprocessable component. Under such a configuration, the loading unit 50 is configured to releasably engage the endoscopic portion 30 in order to facilitate disposal/reprocessing of any single-use component and cleaning and/or sterilization of any reusable component. For a detailed description of the structure and function of exemplary loading units, reference may be made to U.S. Pat. No. 5,752,644, the entire contents of which are incorporated herein by reference. It should be appreciated that principles of the disclosure are equally applicable to surgical staplers having other configurations such as, for example, the types described in U.S. Pat. Nos. 7,334,717, 5,964,394, and 5,915,616, the entire contents of each of which are incorporated herein by reference.

With reference to FIGS. 1 and 2, the handle assembly 100 in accordance with the disclosure is configured to provide power assist when stapling tissue. In contrast to a conventional power handle assembly, the handle assembly 100 may combine manual actuation of a trigger assembly 110 with a power assist from a motor 400 when the load exceeds a predetermined threshold, as will be described. Such a configuration provides a tactile feedback to the clinician. The handle assembly 100 includes a housing 102 having first and second housing halves 102 a, 102 b, a trigger assembly 110 operatively coupled to the loading unit 50 to effect clamping of the jaws and firing of staples, a drive assembly 200, and a motor 400. The trigger assembly 110 is configured to activate the motor 400 based on the size of load applied to the trigger assembly 110 (force needed to squeeze the trigger 112), as will be discussed below.

With particular reference to FIGS. 2-4, the trigger assembly 110 includes a trigger 112, a head portion 120, and a deflection member 118 interconnecting the trigger 112 and the head portion 120 such that when the load (force needed to squeeze the trigger 112) exceeds a predetermined threshold, determined by the size of a gap “G” (FIG. 12) defined between the trigger 112 and the head portion 120, the motor 400 provides the necessary power assist firing staples from the cartridge assembly 56 of the end effector 54. In particular, the gap “G” may be measured by a sensor 116 (FIG. 12) such as, e.g., a magnetic sensor, Hall effect sensor, etc. The sensor 116 may be operatively coupled with, e.g., a printed circuit board 600 including a processor 610, to activate the motor 400. The size of gap “G” may be commensurate with the amount of power assist provided by the motor 400.

With particular reference to FIG. 4, the trigger 112 defines a cavity 112 a configured to receive at least a portion of the deflection member 118. The portion of the deflection member 118 may be secured to the trigger 112 by, e.g., a screw 7. The head portion 120 of the trigger assembly 110 includes a base portion 122 and an anchoring portion 128 extending from the base portion 122. The deflection member 118 is secured to the base portion 122 by, e.g., screws 7. The base portion 122 defines a cavity 124 configured to slidably receive a button 140 therein. The button 140 is coupled to a spring 142 that biases the button 140 laterally outwards. In particular, the spring 142 is interposed between the cap 145 and the button 140. The anchoring portion 128 of the head portion 120 defines a bore 129 that receives a first pivot pin 114 and includes a nose portion 130 disposed proximal of the bore 129. The nose portion 130 is coupled to a spring 171 (FIG. 3, shown in phantom) secured to the housing 102 to bias the trigger 112 to a distal, i.e., unactuated, position. Under such a configuration, the head portion 120 of the trigger assembly 110 is pivotably coupled to the housing 102, which in turn, enables the trigger 112 to pivot with the head portion 120. However, as the load increases, the deflection member 118 deflects and enlarges the gap “G” between the trigger 112 and the head portion 120, which, in turn, may be utilized to activate the motor 400.

With continued reference to FIGS. 2-4, the drive assembly 200 includes a clamping gear 310, a connecting gear 330, a firing gear assembly 350, a drive gear 370, and a rack 390. The clamping gear 310 is rotatably supported about the first pivot pin 114 which extends through the head portion 120 of the trigger assembly 110. The clamping gear 310 defines a cutout 316 (FIG. 7) that receives a tab 144 (FIG. 8) of the button 140. The connecting gear 330 is rotatably supported on the housing 102 about a second pivot pin 117. The connecting gear 330 includes outer teeth 332 that mesh with teeth 312 of the clamping gear 310, and inner teeth 336 (FIG. 3) that mesh with teeth 352 of the firing gear assembly 350. The firing gear assembly 350 is rotatably supported on the housing 102 about the first pivot pin 114.

With particular reference to FIGS. 5 and 6, the firing gear assembly 350 includes a firing gear 356 having teeth 352, and an alignment member 358 coupled to the firing gear 356 by, e.g., screws 7. In addition, the firing gear assembly 350 may further include a bracket 359 to further improve securement of the screws 7 against the firing gear 356. In particular, the firing gear 356 defines an arc shape and defines bores 351 (FIG. 4) positioned radially inward of the teeth 352. The bores 351 receive the respective screws 7. The alignment member 358 is coupled to the firing gear 356 for concomitant rotation therewith as a single construct. The alignment member 358 defines a bore 359 that receives the first pivot pin 114, and proximal and distal slots 358 a, 358 b that receive the tab 144 (FIG. 8) of the button 140.

With brief reference back to FIG. 4, the drive gear 370 is rotatably supported on the housing 102 about a third pivot pin 119. A pair of supports 105 secures the motor 400 and the first, second and third pivot pins 114, 117, 119 to the housing 102. The drive gear 370 includes outer teeth 372, middle teeth 376, and inner teeth 378. In particular, the outer teeth 372 mesh with teeth of a pinion gear 410 that is operatively coupled with the motor 400. The middle teeth 376 mesh with teeth 392 of the rack 390 in order to convert the rotational output of the drive assembly 200 to axial motion of the rack 390. The inner teeth 378 of the drive gear 370 mesh with the outer teeth 332 of the connecting gear 330.

With reference to FIG. 10-12, when the trigger 112 is in the unactuated position, the trigger 112 is biased distally by the spring 171 (FIG. 2) interconnecting the nose portion 130 (FIG. 2) of the head portion 120 of the trigger assembly 110 with the housing 102 (FIG. 1). In addition, the button 140 is biased laterally outwards (FIG. 2) by the spring 142 such that the tab 144 of the button 140 is received in the cutout 316 of the clamping gear 310 and in registration with the distal button slot 358 b of the alignment member 358 in a superposed relation therewith. In addition, the sensor 116 (FIG. 15) of the head portion 120 measures the gap “G” defined between the head portion 120 and the trigger 112. The sensor 116 may be, e.g., a magnetic sensor, or a Hall effect sensor. Any deflection in the deflection member 118 may create or increase the size of the gap “G,” which, in turn, may be utilized to activate the motor 400. For example, the amount of deflection or the amount of increase in the size of the gap “G” may be commensurate with the amount of power assist from the motor 400. The handle assembly 100 may include a printed circuit board 600 (FIG. 4) including a processor 610 in communication with the sensor 116 to activate the motor 400 based on the size of the gap “G” measured by the sensor 116.

With reference to FIGS. 13-17, manual actuation of the trigger 112 by the clinician rotates the clamping gear 310 by the tab 144 of the button 140 received in the cutout 316 of the clamping gear 310. The teeth 312 of the clamping gear 310 mesh with the outer teeth 332 of the connecting gear 330. The outer teeth 332 of the connecting gear 330 further mesh with the inner teeth 378 of the drive gear 370. The middle teeth 376 of the drive gear 370 engage the rack 390 such that rotation of the drive gear 370 is converted to axial motion of the rack 390. The rack 390 is coupled to a drive member 700 for concomitant axial movement therewith. Axial displacement of the drive member 700 is operatively coupled with the loading unit 50 to cause clamping of the jaws and firing of the staples from the loading unit 50 as known in the art. The clamping gear 310, the connecting gear 330, and the drive gear 370 are configured to cause predetermined amount of axial displacement of the rack 390 to enable clamping of the jaws with a single stroke of the trigger 112. In addition, rotation of the connecting gear 330 further rotates the firing gear 356 which engages the inner teeth 336 of the connecting gear 330 such that the alignment member 358 of the firing gear assembly 350 rotates to align the proximal button slot 358 a of the alignment member 358 with the tab 144 of the button 140, while the tab 144 is disposed within the cutout 316 of the clamping gear 310.

With particular reference to FIG. 15, as the trigger 112 is actuated (squeezed in the direction of an arrow “P”), the deflection member 118 is deflected thereby defining the gap “G” between the trigger 112 and the head portion 120, which is measured by the sensor 116. The sensor 116 may be in communication with the processor 610 to activate the motor 400 based on the gap “G.” However, the motor 400 may be configured to be activated to provide power assist only during firing of staples such that the clamping of the jaws is fully completed by the manual actuation of the trigger 112. This can be done by, e.g., setting a threshold load, to activate the motor 400.

With reference now to FIGS. 18-20, when the trigger 112 is squeezed in the direction of the arrow “P,” the jaw members are clamped and the tab 144 of the button 140 is aligned with the proximal button slot 358 a of the alignment member 358. At this time, the clinician may press the button 140 (in the direction of an arrow “I”) such that the tab 144 slides through the proximal button slot 358 a of the alignment member 358, while the trigger 112 is still squeezed.

With reference to FIGS. 21 and 22, while the button 140 is pressed such that the tab 144 slides through the proximal button slot 358 a, the clinician may release the trigger 112 such that the trigger 112 is moved distally in the direction of an arrow “D” by the spring 171 (FIG. 3) connecting the nose portion 130 of the head portion 120 (FIG. 4) to the housing 102 (FIG. 4). As the trigger 112 is moved distally in the direction of the arrow “D,” the tab 144 engages a stop 358d of the alignment member 358. At this time, the clinician may release the button 140 such that the tab 144 is biased into the distal button slot 358 b of the alignment member 358. At this time, the trigger 122 is ready to fire the staples out of the loading unit 50.

With reference now to FIG. 23, as the trigger 112 is squeezed in the direction of an arrow “P,” the tab 144 of the button 140 received in the distal button slot 358 b rotates the alignment member 358, which, in turn, rotates the firing gear 356 in the direction of an arrow “A.” The teeth 352 of the firing gear 356 engage the inner teeth 336 of the connecting gear 330 and rotate the connecting gear 330 in the direction of an arrow “B.” The outer teeth 332 of the connecting gear 330 engage the inner teeth 378 of the drive gear 370 such that rotation of the connecting gear 330 causes rotation of the drive gear 370 in the direction of an arrow “C.” The drive gear 370 engages the rack 390 to convert rotational output of the drive gear 370 to axial movement of the rack 390. The firing gear 356, the connecting gear 330, and the drive gear 370 are configured to advance the rack 370 to a distal-most position (in the direction of arrow “E”) by a single stroke actuation of the trigger 112. In this manner, the drive member 700 (FIG. 2) is advanced to fire the staples out of the loading unit 50. During the advancement of the drive member 700, i.e., while the trigger 112 is being squeezed by the clinician, the sensor 116 measures the gap “G” between the trigger 112 and the head portion 120 such that if the gap “G” is, e.g., above a predetermined threshold, the motor 400 is activated to provide power assist to the firing of the staples. In particular, when the motor 400 is activated, the motor 400 provides a rotational output commensurate with the size or increase in the size of the gap “G.” The pinion gear 410 is coupled to the motor 400 and has teeth 412 that engage the outer teeth 372 of the drive gear 370. In this manner, when the motor 400 is activated, the pinion gear 410 rotates in the direction of an arrow “F,” which, in turn, rotates the drive gear 370 in the direction of the arrow “C,” thereby assisting advancement of the rack 390. This reduces the amount of force required by a clinician to actuate the stapling instrument 10. The motor 400 may also be configured to retract the rack 390. It is further contemplated that the processor 610 may include a feedback system such that when the clinician squeezes the trigger 112 and the gap “G” becomes larger, the motor 400 is activated to reduce the gap “G” with increased speed depending on the size of the gap “G”, whereby the harder the clinician squeezes the trigger 112, the more assistance the motor 400 provides. The parameters of this feedback loop may be adjusted to allow for a higher or lower degree of assistance.

With reference to FIG. 24, the clamping gear 310 is operatively coupled to the connecting gear 330 such that at the end of the firing stroke, the tab 144 of the button 140 is aligned with the cutout 316 of the clamping gear 310. The spring 142 of the head portion 120 biases the button 140 outwards in the direction of an arrow “U” to place the tab 144 in the cutout 316 of the clamping gear 310 such that the tab 144 is disengaged from the firing gear 356 and the trigger 112 is reset.

With reference to FIG. 25, it is further contemplated that the motor 400 may be utilized with a pinion gear assembly 1410 to limit power assist of the motor 400 to the firing of the staples such that clamping of the jaws is effected through the manual actuation of the trigger 112 without assistance from the motor 400. The pinion gear assembly 1410 has a pinion gear 1412 that engages the outer teeth 372 of the drive gear 370 as discussed hereinabove with respect to the pinion gear 410. However, the pinion gear 1412 further includes a rotatable hand 1416 coupled to an output shaft (not shown) of the motor 400 for concomitant rotation therewith, and a boss 1414 configured to engage the rotatable hand 1416 to impart rotation of the rotatable hand 1416 to the pinion gear 1412. Under such a configuration, the output shaft of the motor 400 does not engage the pinion gear 1412 until after the rack 390 has advanced enough to clamp the jaws.

In use, the clinician prepares the surgical site and inserts the loading unit 50 of the surgical stapling instrument 10 through an opening or an incision. Tissue is placed between the jaws of the loading unit 50. Thereafter, the clinician actuates the trigger 112 to manually clamp tissue between the jaws. Thereafter, the button 140 is pressed and the trigger 112 is released to enable firing of the staples. As the clinician actuates the trigger 112, the loading unit fires staples into tissue. The clinician may remove the loading unit 50 from the surgical site by transitioning the loading unit 50 into the clamped configuration.

Persons skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting. It is envisioned that the elements and features may be combined with the elements and features of another without departing from the scope of the disclosure. As well, one skilled in the art will appreciate further features and advantages of the disclosure. Accordingly, the disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. 

1. A handle assembly for use with a surgical stapling instrument comprising: a trigger assembly including: a trigger transitionable between a distal position and a proximal position; a head portion; a button slidably supported in the head portion; and a deflection member interconnecting the trigger and the head portion such that a load applied to the trigger causes the deflection member to flex to define a gap between the trigger and the head portion; a motor configured to be activated based on a size of gap defined by the trigger and the head portion; and a drive assembly including: a clamping gear operatively coupled to the trigger such that actuation of the trigger causes rotation of the clamping gear when the button of the head portion engages the clamping gear; a firing gear assembly operatively coupled to the trigger such that actuation of the trigger causes rotation of the firing gear assembly when the button of the head portion selectively engages the firing gear assembly; a drive gear operatively coupled to the clamping gear, the firing gear assembly, and the motor; and a rack engaged with the drive gear such that rotation of the drive gear causes axial displacement of the rack, wherein when the button of the trigger assembly engages the clamping gear, actuation of the trigger advances the rack by a first distance, and when the button engages the firing gear assembly, actuation of the trigger advances the rack by a second distance greater than the first distance.
 2. The handle assembly according to claim 1, wherein the firing gear assembly includes a firing gear and an alignment member defining proximal and distal button slots configured to selectively receive the button of the trigger assembly.
 3. The handle assembly according to claim 2, wherein when the button engages the clamping gear, actuation of the trigger causes rotation of the clamping gear and the firing gear assembly such that the button is aligned with the proximal button slot of the alignment member.
 4. The handle assembly according to claim 2, wherein the firing gear defines an arc having teeth at a peripheral portion thereof.
 5. The handle assembly according to claim 2, wherein the firing gear and the alignment member are rotatable as a single construct.
 6. The handle assembly according to claim 1, wherein the clamping gear defines a cutout positioned to engage the button of the trigger assembly.
 7. The handle assembly according to claim 1, wherein the head portion is pivotably supported by a first pivot pin.
 8. The handle assembly according to claim 7, wherein the clamping gear and the firing gear are rotatably supported on the first pivot pin.
 9. The handle assembly according to claim 1, wherein the head portion further includes a first spring to bias the button laterally outwards.
 10. The handle assembly according to claim 1, wherein the trigger defines a cavity that receives at least a portion of the deflection member.
 11. The handle assembly according to claim 1, wherein the head portion is coupled to a second spring to bias the trigger towards the distal position.
 12. The handle assembly according to claim 1, wherein the head portion includes a sensor to measure the size of a gap defined between the trigger and the head portion.
 13. The handle assembly according to claim 1, wherein the motor is configured to be activated when the button is engaged with the firing gear assembly.
 14. The handle assembly according to claim 12, further comprising a processor in communication with the sensor to activate the motor based on the size of gap defined between the trigger and the head portion.
 15. A handle assembly for use with a surgical stapling instrument comprising: a trigger assembly including: a trigger; and a head portion including a button movable between first and second positions, the head portion and the trigger defining a gap commensurate with a load applied to the trigger; a motor configured to be activated based on a size of gap defined by the trigger and the head portion; and a drive assembly including: a clamping gear operatively coupled to the trigger such that actuation of the trigger causes rotation of the clamping gear; a firing gear assembly configured to engage the button such that actuation of the trigger causes rotation of the firing gear assembly; a drive gear operatively coupled to the clamping gear, the firing gear assembly, and the motor; and a rack configured to engage the drive gear such that rotation of the drive gear causes axial displacement of the rack, wherein when the button engages the clamping gear, actuation of the trigger advances the rack by a first distance, and when the button engages the firing gear assembly, actuation of the trigger advances the rack by a second distance greater than the first distance and activates the motor that assists advancement of the rack.
 16. The handle assembly according to claim 1, wherein the firing gear assembly includes a firing gear and an alignment member defining proximal and distal button slots configured to selectively receive the button of the trigger assembly.
 17. The handle assembly according to claim 16, wherein the button engages the distal button slot of the alignment member when the trigger is actuated to advance the rack by the second distance.
 18. A surgical stapling instrument comprising: a loading unit including first and second jaws having a staple cartridge assembly and an anvil assembly, respectively; a handle assembly including: a housing; a trigger assembly including: a trigger; and a head portion pivotably coupled to the housing and movable relative to the trigger, the head portion including a button slidably supported in the head portion; a motor configured to be activated based on a gap defined between the trigger and the head portion; and a drive assembly including: a clamping gear operatively coupled to the trigger such that actuation of the trigger causes rotation of the clamping gear when the button of the head portion engages the clamping gear; a firing gear assembly operatively coupled to the trigger such that actuation of the firing gear assembly causes rotation of the firing gear assembly when the button of the head portion engages the firing gear assembly; a drive gear operatively coupled to the clamping gear, the firing gear assembly, and the motor; and a rack configured to engage the drive gear such that rotation of the drive gear causes axial displacement of the rack; and a drive rod operatively coupling the rack with the loading unit, wherein when the button engages the clamping gear, actuation of the trigger advances the drive rod by a first distance to clamp the first and second jaws together, and when the button engages the firing gear assembly, actuation of the trigger advances the drive rod by a second distance greater than the first distance to fire staples from the staple cartridge assembly.
 19. The surgical stapling instrument according to claim 18, wherein the firing gear assembly includes a firing gear and an alignment member defining proximal and distal button slots configured to selectively receive the button of the trigger assembly.
 20. The surgical stapling instrument according to claim 19, wherein when the button engages the clamping gear, actuation of the trigger causes rotation of the clamping gear and the firing gear assembly such that the button is aligned with the proximal button slot of the alignment member.
 21. The surgical stapling instrument according to claim 20, wherein the button engages the distal button slot of the alignment member when the trigger is actuated to advance the rack by the second distance. 